Most people think cold spots happen because the HVAC unit is too small, the vent is weak, or the wall unit “isn’t pushing air far enough.”
Mike Sanders knows better.
Cold spots are almost never about total BTUs.
They’re about geometry—the shape of the room, the pathways air can travel, and the obstacles that distort circulation.
Mike’s 4-Point Airflow Compass is a system he developed after decades of rebalancing rooms, studying stagnant pockets, inspecting airflow collapses behind furniture, and mapping out the unseen “wind” patterns inside homes.
It’s simple, scientific, incredibly accurate, and stunningly consistent across:
-
bedrooms
-
apartments
-
living rooms
-
basements
-
bonus rooms
-
offices
-
studio layouts
-
and even oddly angled great rooms
This long-form guide breaks down the full Compass framework, step-by-step, showing exactly how Mike predicts cold spots before they form, then modifies airflow geometry to eliminate them for good.
🌬️ 1. Mike’s Core Principle: “Air Doesn’t Fill a Room. It Fills a Path.”
Most airflow problems happen because homeowners imagine air spreads like water poured into a bowl.
But air doesn't “fill” anything.
It follows a path, and that path is controlled by:
-
walls
-
angles
-
doorways
-
objects
-
thermal gradients
-
pressure differences
As Mike says:
“Cold spots aren’t random. They’re shadows. Airflow shadows.”
The 4-Point Airflow Compass is how Mike identifies those shadows.
🧊 2. The Airflow Geometry Theory Behind the Compass
The Compass is based on how air:
-
moves across open spaces
-
wraps around obstacles
-
loses energy at edges
-
accelerates through bottlenecks
-
avoids dead-end corners
-
falls into low-pressure floor zones
Airflow geometry combines:
-
fluid dynamics
-
thermodynamics
-
room layout
-
object resistance
-
pressure mapping
Mike simplifies all this into the four directions the air wants to move:
-
North-Throw (primary forward airflow)
-
South-Return (floor-level return path)
-
East-Spread (lateral distribution)
-
West-Drift (thermal pull or window-driven flow)
Together, these form the 4-Point Airflow Compass.
🧭 3. The 4-Point Compass Overview
Here is Mike’s Compass at a glance:
🔼 Point 1 – North-Throw (Primary Force Zone)
Where the conditioned air FIRST travels.
🔽 Point 2 – South-Return (Return Path Zone)
Where the air eventually RETURNS to the unit.
➡️ Point 3 – East-Spread (Lateral Movement Zone)
Where the air spreads across the room horizontally.
⬅️ Point 4 – West-Drift (Thermal Pull Zone)
Where thermal differences PULL air (windows, doors, cold walls).
Every cold spot forms when one of these four Compass directions collapses.
📍 4. Point 1: North-Throw — The Primary Airflow Direction
North-Throw is the strongest, fastest, most focused part of the airflow.
Where cold spots occur:
-
just beyond the throw limit
-
behind tall furniture blocking the throw
-
at the far-left or far-right edge of the throw beam
-
in alcoves or corners the throw never reaches
Geometry rules Mike uses:
1️⃣ The Throw Has a Shape
Air doesn’t expand like a cone—
it expands like a flattened oval.
That means:
-
top and bottom edges lose force quickly
-
lateral edges taper
-
center remains strongest
2️⃣ The Throw Stops at Resistance
Resistance includes:
-
sofas
-
beds
-
entertainment centers
-
desks
-
cabinet ends
-
high back chairs
3️⃣ The Throw Must Hit a Wall to Circulate
Without a wall to deflect off:
-
the airflow stalls
-
becomes a “blob”
-
creates a temperature bubble
📚 Use North-Throw Mapping to Predict:
-
cold corners behind furniture
-
under-window cold pockets
-
mid-room dead zones
-
areas the airflow will NEVER reach
📉 5. Point 2: South-Return — The Floor-Level Return Loop
Mike calls this the most misunderstood part of airflow.
Every room must have a return path, even if it’s not a mechanical return duct.
The room becomes a pressure loop:
-
air moves forward at head level
-
loses energy
-
falls
-
crawls along the floor
-
returns to the intake
If the return path gets blocked, cold spots form instantly.
Where cold spots form:
-
behind sofas touching walls
-
next to beds with skirts
-
behind dressers
-
inside tight corners
-
behind recliners
-
in narrow hallways off the main room
-
under windows where cold air pools
Geometry rules Mike uses:
1️⃣ The Return Travels Along Walls
Just like rivers form along terrain edges, return airflow forms along wall edges.
If furniture blocks these edges, the return collapses.
2️⃣ Return Air Prefers the Shortest Path
If the unit is centered, the return path becomes symmetric—
and often stalls on both sides.
This is why Mike rarely installs units in the center.
3️⃣ Cold Air Is Lazy
Cold air:
-
stays low
-
moves slowly
-
sticks to corners
-
resists movement unless pushed or pulled
📚 Use South-Return Mapping to Predict:
-
cold corners
-
cold floors
-
floor-level humidity pockets
-
drafty-feeling walking paths
🌬️ 6. Point 3: East-Spread — The Horizontal Air Distribution Zone
This identifies how far the airflow spreads left and right.
Where cold spots form:
-
far side corners the throw never reaches
-
areas behind tall furniture
-
corner alcoves
-
segmented L-shaped sections
-
off-axis rooms behind partial walls
Geometry rules Mike uses:
1️⃣ Air Spreads Outward but Not Backward
The airflow expands sideways in a forward arc.
It does not backfill the area behind the unit effectively.
This creates the classic cold pocket behind the unit wall.
2️⃣ Lateral Spread Is Cut by Furniture
Tall furniture narrows the spread dramatically.
Common spread killers:
-
tall dressers
-
bookshelves
-
TV stands
-
sectional chaise ends
-
bunk beds
3️⃣ Spread Collapses in Rooms with Odd Shapes
The more irregular the room geometry:
-
the weaker the spread
-
the more cold corners you get
📚 Use East-Spread Mapping to Predict:
-
drafty left/right extremes
-
temperature imbalances from wall to wall
-
“cold shadows” behind furniture
🌡️ 7. Point 4: West-Drift — Thermal Drift & Window-Induced Flow
Mike learned this from years of watching how windows trick the air.
Cold Spots Here Are Caused By:
-
cold window glass
-
drafty frames
-
sun-to-shadow transitions
-
uninsulated exterior walls
-
corner thermal pooling
This is the Compass direction most homeowners never consider but affects 30–50% of all cold spots.
Geometry rules Mike uses:
1️⃣ Windows Create Downward Currents
Cold window = falling air = floor-level cold spot.
2️⃣ Exterior Walls Pull Air
Walls colder than interior air create:
-
micro-pressure drops
-
horizontal drift
-
air sliding along the wall
3️⃣ Any Imbalance Creates a “Thermal Vortex”
This tiny vortex:
-
traps cold air
-
prevents mixing
-
forms stable cold pockets
📚 Use West-Drift Mapping to Predict:
-
under-window cold spots
-
cold along entire exterior walls
-
corner pockets where two exterior walls meet
🔍 8. How Mike Uses the Compass to Predict EXACT Cold Spot Locations
Mike follows a process:
1️⃣ Draw the Shape of the Room
He marks:
-
walls
-
windows
-
doors
-
furniture
2️⃣ Plot the North-Throw
He draws the throw oval pattern.
Any areas outside the oval may become cold.
3️⃣ Plot the South-Return
He traces return flow along walls.
Blocked paths become cold zones.
4️⃣ Plot East-Spread Limits
He charts how far air spreads sideways.
Areas outside the arc become stagnant.
5️⃣ Plot West-Drift Influence
He marks:
-
window locations
-
cold walls
-
shaded corners
These drift zones create cold pools.
6️⃣ The Overlap of Weak Zones Indicates Cold Spots
Cold spots ALWAYS fall at the intersection of:
-
weak throw
-
blocked return
-
poor spread
-
strong drift
This triangulation is Mike’s secret.
It’s unbelievably reliable.
🛠️ 9. Mike’s Fixes for Each Compass Direction
Once a cold spot is predicted, he fixes the underlying geometry.
Fixing North-Throw Issues
-
redirect vanes
-
use a slight downward angle
-
move furniture
-
reposition the unit off-center
Fixing South-Return Issues
-
open floor pathways
-
raise furniture slightly
-
add a micro floor fan
-
increase door undercut
Fixing East-Spread Issues
-
remove tall blockages
-
adjust furniture
-
add a cross-flow booster fan
Fixing West-Drift Issues
-
insulate windows
-
add blinds/thermal curtains
-
use micro-fan to break downdraft
-
redirect airflow toward the window
📈 10. Real-World Examples of the Compass in Action
🏠 Case Study 1: Cold Corner Behind the Sofa
Compass analysis:
-
throw blocked
-
return path blocked
-
window downdraft nearby
Fix:
-
move sofa 3 inches
-
angle vanes down
-
thermal curtains on window
Cold spot eliminated in minutes.
🛏️ Case Study 2: Cold Bedroom Closet Area
Compass revealed:
-
zero throw penetration
-
zero lateral spread
-
strong return loop collapse
Fix:
-
add floor-level circulator
-
open return path
-
off-center placement
🪟 Case Study 3: Freezing Under-Window Pocket
Compass showed:
-
heavy west drift
-
no throw coverage
-
return path too weak
Fix:
-
redirect airflow toward window
-
small sill fan
-
close curtain during peak sun
📊 11. Performance Gains From Using the 4-Point Compass
Homeowners typically experience:
✔ 80% reduction in cold spots
✔ more even temperature distribution
✔ better humidity balance
✔ 15–30% improved heating performance
✔ quieter airflow
✔ faster system recovery time
✔ less cycling = lower energy bills
🔗 External Verified Sources
-
DOE Insulation & R-Value Overview
https://energy.gov/energysaver/weatherize/insulation -
FLIR – Thermal Imaging Basics
https://www.flir.com/discover -
EPA Moisture & Mold Control
https://www.epa.gov/mold -
Window & Door Flashing Principles (relevant to sleeve flashing)
https://www.energy.gov/energysaver/design/windows-doors-and-skylights -
ACCA Manual J Load Guidelines
https://www.acca.org/hvac-design/manual-j
